1. Field of the Invention
The present invention relates to an antipenetrating agent, a solvent ink for inkjet printing, and a printing method.
2. Discussion of the Background
Inkjet printing using such a solvent ink is widely used in printing for signs such as advertising displays and large-sized posters. Generally, solvent ink contains organic solvent (for example, a glycol ether compound or cyclohexanone) as a main component and further contains a colorant such as dye or pigment and a binder resin.
In the inkjet printing using the solvent ink, a printed matter is obtained in the following manner. First, the solvent ink is ejected from an inkjet head and is deposited on a print medium to form an image. The solvent in the solvent ink deposited on the print medium is absorbed in the print medium or removed from the printed surface by heating the print medium. Consequently, dried ink adheres tightly to the printed surface to form an ink coating, thereby obtaining a printed matter.
As print media used for the inkjet printing using the solvent ink, PVC sheets and tarpaulins having solvent-absorption property have been typically used. Recently, in addition to these print media, print media having hydrophilic porous print surface such as ink-jet print paper and plate member for offset printing are also used for the inkjet printing using the solvent ink.
As the solvent ink used in the inkjet printing, for example, JP-A-2001-311023 discloses a solvent ink containing resin particles, JP-A-2004-224910 discloses a solvent ink containing hydrophobic polymer which has a glass transition temperature (Tg) of 40° C. or more, and JP-A-6-240192, JP-A-10-140060 and JP-A-10-195356 disclose solvent inks containing predetermined resins. The contents of these publications are incorporated herein by reference in their entirety.
However, the solvent inks disclosed in JP-A-2001-311023, JP-A-2004-224910, JP-A-6-240192, JP-A-10-140060, and JP-A-10-195356 have a problem that ink bleed easily occurs in the obtained image. In addition, when inkjet printing is performed onto a plate member for offset printing (hereinafter, sometimes referred to as “offset printing plate member”) by using the aforementioned conventional solvent ink, the ink penetrates into the print medium so as to reduce the amount of ink coating formed on the printed surface. Accordingly, the ink coating on the obtained offset plate has insufficient water resistance and insufficient water repellency. When this offset plate with the insufficient amount of ink coating is used for the offset printing, the adhesion of ink for offset printing relative to the offset plate is poor, that is, there is a problem that sufficient plate life is not obtained.